1. Technical Field
The present invention relates generally to universal joints having cross-member journals provided with internal lubrication channels which open at the ends of the journals to provide for replenishment of lubricant in bearing cups within which the journals are pivotally supported in respective yoke members, and in particular, to such a universal joint having a washer and lubrication baffle press-fit within an enlarged end portion of the lubrication channel.
2. Related Art
Typically, within the cross-members or trunnions of a universal joint, the lubrication channels intersect at a central location, adjacent an external lubrication fitting, whereby lubricant can be introduced to the universal joint when required, as shown in U.S. Pat. No. 4,103,512 to McElwain, et al. The lubricant introduced to the central location of the universal joint typically flows radially outward towards the ends of the cross-member journals through the individual lubrication channels. During operation, the rotational movement of the universal joint about an axis perpendicular to the cross-members generates centrifugal forces which assists the outward flow of lubricant to the bearing cups.
When rotation of the universal joint is stopped, one or more of the journals may be disposed in a vertically upward orientation, such that the force of gravity acts to draw lubricant back downward from the bearing cups and into the lubrication channels. Upon resumption of rotational motion, the associated bearing caps may be left with little or no lubricant, resulting in higher frictional forces and undesired wear.
In addition to the use of lubricant to reduce frictional wear between the cross-member ends and bearing caps, manufacturers often dispose a thrust washer as a buffer between the inner surface of the bearing cap and the cross-member or trunnion end, such as is shown in U.S. Pat. No. 6,264,566 B1 to Nieman et al., or in U.S. Pat. No. 5,813,916 to Lentini, et al. During manufacture, these thrust washers are installed in the bearing caps prior to placement over the cross-member ends, using spacers to ensure proper location. The corresponding faces of the cross-member ends are ground in a machining operation to ensure a desired tolerance for the thrust washers, and are pressed to provide for one or more lubrication grooves facilitating a flow of lubricant between the thrust washer and the cross-member end.
Accordingly, it is an object of the present invention to overcome the potential problems associated with lubricant drainage from the proximity of the bearing cups in a universal joint while simultaneously eliminating one or more grinding and machining steps from the universal joint manufacturing process.